Bulkhead



2 Sheets-Sheet 1 H. 8. LEE ET AL BULKHEAD Sept. 10', 1968 Original Filed Nov.

INVENTOR. HERBERT S. LEE JAMES F. O'CONNER W M r- V ATTORNEYS Sept. 10, 1968 H, 5 LEE ET AL. 3,400,437

BULKHEAD Original Filed Nov. 20, 1961 I 2 Sheets-Sheet 2 INVENTOR. HERBERT $.LEE JAMES F. O'CONNER mmwv ATTORNEYS United States Patent 3,400,437 BULKHEAD Herbert S. Lee, Los Alamitos, and James F. OConner, Los Angeles, Calif., assignors to American Pipe and Construction Co., Monterey Park, Calif., a corporation of California Original application Nov. 20, 1961, Ser. No. 155,531, new Patent No. 3,193,901, dated July 13, 1965. Divided and this application May 10, 1965, Ser. No. 454,569

8 Claims. (Cl. 25-128) ABSTRACT OF THE DISCLOSURE A bulkhead for sealing one end of an inflatable tubular envelope, having a wall member adapted to be inserted in the end of the tubular envelope, and an expansible perimeter mounted on the wall member and adapted to be expanded into engagement with the envelope to seal the end of the envelope.

The present invention constitutes a division of our application entitled Cast-in-Place Pipe Apparatus and Method, Ser. No. 155,531, filed Nov. 20, 1961, issued as U. S. Patent No. 3,193,901, on July 13, 1965.

This 7 invention relates to a removable bulkhead for pneumatically sealing an opening. It is particularly adaptable for use with apparatus for producing cast-in-place pipe which utilizes an inflatable tubular envelope to define a core member for supporting cementitious material until it takes a permanent set. The removable bulkhead pneumatically seals one end of the tubular core member. The core member may then be pressurized.

Although the use of inflatable core members is not new, the methods and apparatus previously employed have not proven to be entirely satisfactory, primarily since the cost of the inflatable core members was high compared with their life expectancy; The present invention contemplates apparatus that can utilize an inflatable tubular envelope made of thin, pliable and inexpensive material and provides a bulkhead for use in connection therewith. The envelope is initially sealed and anchored at one end by the bulkhead, through which the envelope is inflated with fluid pressure. A second bulkhead (not necessarily of the inventive design) is provided at a spaced distance from the first bulkhead; and while this second bulkhead is advanced, increasing the inflated length of the envelope, the newly inflated sectional lengths are progressively encased with cementitious material. By virtue of this progressive system of inflation and encasement, the cementitious material can be gradually deposited upon the envelope.

It is therefore an object of the invention to provide bulkhead means comprising a wall member having an expansible periphery that may be expanded into engagement with the inflatable envelope and a pre-cast pipe section, thereby clamping said envelope to said pipe section and substantially sealing said envelope against fluid pressure leakage.

Another object is to provide apparatus of the kind described in the preceding object wherein said expansible periphery is inflatable.

3,400,437 Patented Sept. 10, 1968 A further object is to provide a bulkhead having a wall member for use in apparatus as described wherein said wall member contains one or more pressure relief valves for limiting the pressure confined within the inflatable envelope.

Another object is to provide a bulkhead for sealing one end of an inflatable tubular envelope comprising a wall member adapted to be inserted within the end of a tubular envelope, said wall member having a peripheral rim defining an exterior channel, an inflatable tube disposed within the channel of said rim and circumscribing said wall member, and a resilient garter ring also adapted to be disposed within the channel for securing said envelope to said rim after being placed around said envelope.

Other objects of this invention will become more readily apparent in view of the following description and the accompanying drawings.

In the drawings, forming a part of this invention and in which like parts are identified by like reference numerals throughout the same,

FIG. 1 is a longitudinal vertical section of one form of apparatus for producing cast-in-place pipe in connection with which the bulkhead comprising the present invention may be employed;

FIG. 2 is an enlarged horizontal section of the stationary bulkhead shown in FIG. 1;

FIG. 3 is a section taken on lines 33 of FIG. 2;

FIG. 4 is an enlarged detail section taken on lines 44 of FIG. 3.

With reference to FIG. 1, the bulkhead 10 is shown in place in association with apparatus 11 for producing castin-place pipe 12b in trench 13. Apparatus 11 includes rotatable auger 14 which is coaxially disposed with slip form sleeve 15 to convey concrete 16 from hopper 17 into the space between auger 14 and cylindrical housing 18. Tubular core member 19 is accordion folded in cartridge 20 and extends from bulkhead 10 to bulkhead 21. As apparatus 11 moves from the left to the right as viewed in FIG. 1, auger 14 forces concrete 16 into a cylindrical form. Inner core member 19 is paid out to provide support for the pipe 12 after it loses its support by slip form sleeve 15. The support is provided by pressure in the generally cylindrical volume defined by bulkhead 10, core member 19, and bulkhead 21.

Envelope 19 is fluidly sealed at a fixed or stationary end by bulkhead 10, as shown in FIG. 1. A pre-cast section of pipe 12a, or other form member having substantially the same internal circumference as the exterior circumference of the envelope 19, is initially used to begin the process of pipe manufacture. As best seen in FIG. 2, pipe section 12a is restrained from backward movement by a bracing means comprising a pair of timbers 22 and a screw jack 23. One timber member is placed on either side of the trench 13 within which the pipe is to be cast, and the screw jack 23 is used to spread the timbers apart, forcing them into the walls of the trench. Each timber provides a surface portion laterally inwardly of the trench against which the cast-in-place pipe section is placed, said timbers restraining further rearward movement of the pipe section.

With reference to FIGS. 2-4, bulkhead 10 is comprised of a wall member 24 having a peripheral rim 25 defining an exterior channel, and an inflatable tube 26 or other expansible means is disposed peripherally thereof. Tube 26 resembles the tire of a vehicle having a valve stem 27 protruding inwardly through rim 25. An elastic ring 28 is used for securing envelope 19 peripherally of rim 25 before bulkhead 10 is placed within a pre-cast pipe section; and four quardantly spaced fastening screws 29 are used for anchoring the bulkhead to the pre-cast pipe 12a.

Wall member 24 contains a pair of pressure relief valves 30, each valve comprising a valve plate 31 reciprocally mounted on a valve stem 32 from a cross arm support 33 and biased toward a closed position by a helical compression spring 34. A pair of lock nuts 35 is threaded upon the valve stem, and by rotatably adjusting their axial position the compression force of the valve springs may be controlled. It will be apparent that the relief valves are employed to limit the fluid pressure force applied within envelope 19.

Compressor means comprising for example a gasoline powered engine and blower, is fluidly connected to the interior of envelope 19 by a flexible conduit 38 through an opening in wall member 24. A second conduit line 39 provides fluid communication between the interior of the envelope and a manometer which indicates the instantaneous fluid supporting pressure within the envelope.

To start the process of casting a pipe in place, the piece of pre-cast pipe 12a, or a metal form, is placed within the trench 13. Timbers 22 and jack 23 are then installed for restraining the pipe against backward movement. The extruding machine is placed adjacent to the pre-cast pipe section with the slip form sleeve actually disposed within said pipe section. Envelope 19 is then pulled through the machine and pre-cast pipe 12a whereupon stationary bulkhead assembly 10 is secured thereto by elastic ring 28, said envelope extending over the tube 26. The bulkhead assembly is slipped into the rearmost end of the pre-cast pipe, and while supported in a vertical position, tube 26 is inflated forming a fluid pressure seal. After inflation of tube 26, which centers the bulkhead 10 relative to pipe section 12a, screws 29 are tightened to secure the bulkhead to the pipe section and thereby preventing the fluid pressure that is to be applied within envelope 19 from blowing the bulkhead out of the pipe section. The apparatus is now conditioned to begin operation.

The blower means is. stated, supplying air pressure into envelope 19 and causing an inflation thereof between bulkheads 10 and 21. The amount of air pressure used will necessarily depend upon the diameter of pipe being cast as well as the wall thickness of the pipe. However, an internal pressure of 6 oz./sq. in. has been effectively used in casting a pipe of 24" internal diameter. Inasmuch as the entire envelope is contained by the more durable and rigid bulkhead surfaces and the interior confines of the precast and cast-in-place pipe sections, there is no tendency for the envelope to be enlarged beyond its normal inflated size, provided, of course, that the internal pressure does not become excessive. For this reason, and also to prevent rupturing of the envelope, pressure relief valves 30 are utilized to insure that a near constant pressure level is maintained. The pressure level may be checked by the manometer.

After a suflicient time has elapsed for the concrete pipe to take a set, the blower may be turned off and the pipe exposed to atmosphere. Bulkheads 10 and 21 and envelope 19 are then removed from the pipe, and an end joint is provided.

Having thus described the invention, we claim:

1. Bulkhead apparatus of the kind described for sealing one end of an inflatable tubular envelope against a tubular form comprising: a tubular envelope, a wall member inserted within the end of staid tubular envelope, means defining an expansible perimeter mounted on said wall member, and means for expanding said perimeter into engagement with said envelope to seal the end of said envelope.

2. The bulkhead apparatus of claim 1 wherein said expansible perimeter means is inflatable with fluid pressure.

3. The bulkhead apparatus of claim 1 wherein said wall member is provided with a pressure relief valve for limiting the pressure confined within the envelope by said bulkhead.

4. The bulkhead apparatus of claim 1 and further including means for securing said bulkhead to the inner surface of said tubular form to prevent relative axial movement therebetween.

5. The bulkhead apparatus of claim 1 and further including a resilient ring for securing said envelope to a peripheral surface of said wall member.

6. Bulkhead apparatus of the kind described for sealing one end of an inflatable tubular envelope against a tubular form comprising: a tubular envelope, a wall member inserted within the end of said tubular envelope, said wall member having a peripheral rim defining an exterior channel, an inflatable tube disposed within the channel of said rim and circumscribing said wall member, means for inflating said tube, and a resilient garter ring also disposed within the channel for securing said envelope to said rim after being placed around said envelope.

7. The bulkhead apparatus of claim 6 and further including means for securing said wall member to said tubular form to prevent relative axial movement therebetween.

8. The bulkhead apparatus of claim 6 wherein said wall member is provided with a pressure relief valve for limiting the pressure confined within the envelope by said bulkhead.

References Cited I. SPENCER OVERI-IOLSER, Primary Examiner.

.R. D. BALDWIN, Assistant Examiner. 

